Understanding your CD maturity result
The table below contrasts a CD with a standard savings account on the features that most directly affect the maturity calculation.
| Feature | Certificate of deposit (CD) | Standard savings account |
|---|---|---|
| Rate | Fixed for the full term | Variable; can change at the institution's discretion |
| Access to funds | Restricted until maturity, subject to an early withdrawal penalty | Generally accessible at any time, subject to account terms |
| Maturity value | Can be calculated precisely in advance from the fixed rate and term | Cannot be precisely predicted in advance since the rate may change |
- This calculator assumes no withdrawals occur before maturity; an early withdrawal typically triggers a penalty specified in the CD's terms, which usually forfeits some amount of interest and can, in some cases, reduce the principal returned.
- FDIC deposit insurance applies to CDs at member institutions up to the standard coverage limits per depositor, per insured bank, per ownership category, the same as other covered deposit account types.
- Some CDs offer a bump-up or step-up rate feature, or automatically renew into a new CD term at maturity unless the depositor takes action; this calculator assumes a single fixed rate held constant for the entire stated term.
What is a certificate of deposit (CD)?
A certificate of deposit (CD) is a time deposit offered by banks and credit unions that pays a fixed interest rate in exchange for the depositor agreeing to leave the funds untouched for a set term, ranging commonly from a few months to several years. The FDIC insures CDs at member banks up to the standard deposit insurance limits, the same as other deposit account types.
Because the rate and term are fixed at the time of deposit, a CD's maturity value can be calculated precisely in advance, unlike a variable-rate savings account. Withdrawing funds before the CD's maturity date typically triggers an early withdrawal penalty, which usually forfeits some amount of interest and, in some cases, can reduce the principal returned.
CD rates and terms vary by institution, and longer terms do not always guarantee higher rates — rate offerings depend on current market interest rates and each institution's specific CD products at the time of deposit.
How to use this CD calculator
- Enter the deposit (principal) amount.
- Enter the annual interest rate offered on the CD.
- Enter the CD term in months.
- Select the compounding frequency stated by the institution — daily, monthly, quarterly, or annually.
- Read the maturity value, total interest earned, and the equivalent APY for the CD.
The formula behind CD maturity value
Maturity value uses the standard compound interest formula, applying the periodic rate (annual rate divided by compounding periods per year) across the CD's full term expressed in years. Interest earned is simply the maturity value minus the original deposit, and the equivalent APY is calculated the same way as any deposit account APY, based on the compounding frequency.
On the calculator's default example — a $10,000 deposit at 4.5% compounded monthly for an 18-month term — the maturity value is $10,696.95, interest earned is $696.95, and the equivalent APY is 4.594%.
Common mistakes
- Withdrawing funds from a CD before maturity without accounting for the early withdrawal penalty, which typically reduces the interest actually received below what this calculator's full-term maturity value shows.
- Assuming a longer CD term always earns a higher rate — actual rate offerings depend on current market conditions and the specific institution's CD products, and shorter-term CDs sometimes offer competitive or even higher rates than longer terms.
- Confusing the nominal rate with the equivalent APY — the compounding frequency affects the true annual yield, which is why this calculator reports both figures.
- Not confirming whether a CD automatically renews at maturity, potentially at a different rate, if no action is taken — many institutions have a short grace period after maturity to withdraw or make changes before automatic renewal.
- Assuming all CD interest above the deposit is tax-free — CD interest is generally taxable as ordinary income in the year it is earned or credited, regardless of whether it is withdrawn, unless held in a tax-advantaged account.
자주 묻는 질문
How much does a $10,000 CD at 4.5% for 18 months earn?
At 4.5% compounded monthly over an 18-month term, a $10,000 CD grows to a maturity value of $10,696.95, earning $696.95 in interest, which is equivalent to an APY of 4.594%.
What happens if I withdraw money from a CD before it matures?
Most CDs charge an early withdrawal penalty specified in the account terms, which typically forfeits some amount of accrued or future interest and, depending on the institution and how early the withdrawal occurs, can in some cases reduce the principal returned as well.
Are CDs FDIC insured?
Yes, CDs held at FDIC-member banks are covered by federal deposit insurance up to the standard coverage limits, calculated per depositor, per insured bank, per ownership category — the same insurance framework that covers other deposit account types like checking and savings accounts.
Is CD interest taxable?
Generally, yes. CD interest is typically taxable as ordinary income in the year it is earned or credited to the account, even if the CD has not yet matured and the interest has not been withdrawn, unless the CD is held within a tax-advantaged account such as an IRA.
What is the difference between a CD's interest rate and its APY?
The interest rate is the nominal annual rate before accounting for compounding, while the APY reflects the actual annual yield including the effect of the CD's compounding frequency. The APY will always be equal to or slightly higher than the nominal rate, with the gap depending on how often interest compounds.
참고 자료
- Federal Deposit Insurance Corporation (FDIC). Certificates of deposit: know the basics. fdic.gov.
- Federal Deposit Insurance Corporation (FDIC). Deposit insurance coverage limits and ownership categories. fdic.gov.
- Federal Reserve Board. Regulation DD — Truth in Savings Act implementing regulation. federalreserve.gov.
- Consumer Financial Protection Bureau (CFPB). What is a CD (certificate of deposit)? consumerfinance.gov.